This invention relates to a an apparatus useful therein, for distributing blood on, say, a glass slide for subsequent inspection with a microscope. Such distribution if often referred to as "filming" by those working in medical laboratories.
There are a number of problems associated with the distribution of a blood sample on a glass slide. Perhaps the most obvious problem is that of obtaining an even distribution over the entire slide. The usual manual method consists of placing a drop of blood on the slide and then using a second slide to smear the blood along the slide. This technique usually results in poor lateral distribution, and the excessively narrow smear along the slide usually consists of excessively thick and ultra-thin areas. To avoid such problems, centrifugal equipment was introduced which utilized centrifugal force to spread blood along the length of a spinning slide and utilized the acceleration of the slide to achieve a lateral distribution of the blood.
This centrifugal procedure is a substantial advance in filming, but it has at least two problems associated therewith: one of these relates to formation of aerosols and their distribution by air currents inherent in fast-rotating centrifugal devices. Clinical experience suggests that diseased samples may be a source of disease-bearing contaminants when processed in such devices unless adequate protective measures are taken. Another problem relates to excess blood being thrown off from the slide and collecting within the rotor enclosure. The problem is not only aesthetic in nature, but also involves additional cleaning and maintenance requirements and an undesirable threat of contamination of samples, and of equipment from samples, during handling. Such equipment contamination can also affect operation of the mechanisms of the centrifugal device.